With the development of liquid crystal panel, great technological skills for manufacturing liquid crystal products are required.
During the conveyance process of liquid crystal panel substrates, take a TFT (thin-film transistor) glass as the substrate for an example, during conveyance, basically, the TFT glasses are conveyed through cassettes, wherein there are two types of cassette conveyance.
The first type of cassette conveyance is random cassette conveyance, which has the advantage of flexibility on selecting which TFT glass is to be conveyed, but has the disadvantage of having a limited number of TFT glasses for a period of conveyance that leads to low production efficiency.
The second type of cassette conveyance is sequential cassette conveyance, which has the advantage of being capable of conveying more TFT glasses, but cannot rapidly select the desired TFT glass to convey.
Since the type of sequential cassette conveyance has better efficiency, most conventional technologies adopt this type of conveyance to convey liquid crystal panel substrates. With reference to FIGS. 1a to 1c, FIGS. 1a to 1c are schematic views of cassette structures used for conveying liquid crystal panel substrates using the sequential cassette conveyance type, wherein FIG. 1a is a front view, FIG. 1b is a side view, FIG. 1c is a bottom view showing wheels and supporting ropes supporting a substrate, and FIG. 1d is a side view of FIG. 1c. 
With reference to FIGS. 1a and 1b, a cassette 10 has multiple left side pillars 11 and multiple right side pillars 12, and the cassette 10 has multiple slots 13 formed therein. When conveying a liquid crystal panel substrate (as shown in FIG. 1c), the liquid crystal panel substrate, such as a TFT glass, is inserted in one of the slots 13. With reference to FIG. 1b, the substrate of liquid crystal moves in and out of the cassette 10 along a horizontal direction A.
With reference to FIGS. 1c and 1d, the cassette 10 has multiple wheels 14 mounted on a bottom thereof, and further has multiple supporting ropes 15 supporting the liquid crystal panel substrate.
In the process of conveying the liquid crystal panel substrates, once a certain one of the liquid crystal panel substrates is selected to be removed, the substrates under the selected substrate will have to be orderly removed from bottom to top via the rotation of the wheels 14, and after that the selected liquid crystal panel substrate then can be move out, and it takes a lot of time in such process.
For example, with reference to FIGS. 2a and 2b, FIG. 2a is a side view of the liquid crystal panel substrates inserted and arranged in slots of the cassette, which include a first substrate 21, a second substrate 22, a third substrate 23, . . . , and a Nth substrate 2N. When the third substrate 23 is to be move out for inspection, substrates (24 to 2N) under the third substrate 23 will have to be moved out first, and then the third substrate 23 can be moved out. After inspecting the third substrate 23, the other substrates (24 to 2N) then will be inserted back to their original places. The process not only takes a lot of time, but also has low efficiency that limits the production capacity of liquid crystal panel.
In conclusion, time-consuming problem on moving out the liquid crystal panel substrates from the conveyor apparatus, which leads to low efficiency and limited production capacity of liquid crystal panel, has become one of the technical problems to be solved in the field of manufacturing liquid crystal products.